Field of the Invention
This invention relates to chemical analyzers which automatically analyze fluids, and more particularly relates to “dry chemistry” analyzers. Even more specifically, this invention relates to chemical analyzers that are particularly adapted for biological fluid testing purposes wherein a change in an optical characteristic of a sample is sensed and analyzed automatically by the analyzer. The analyzer of the present invention has particular utility for human and veterinary applications.
Description of the Prior Art
Automated systems have been developed for carrying out quantitative chemical analysis of fluid samples using essentially dry, analytical elements, which elements offer substantial storage and handling conveniences. The “dry” analytical elements are preferably in the form of test slides. These test slides are formed as a multi-layer element containing the necessary free agents for reaction with components of a biological fluid, such as a blood serum, deposited thereon. Certain reactions colorimetrically produce a change in optical density, or fluoresce, which is sensed by a reflectormeter or fluorometer, the amount of light reflected from or fluoresced by the test element varying in accordance with the reaction and being indicative of the amount of a particular component present in the fluid. Such test slides containing a dry analyte are well known in the art and are described in U.S. Pat. No. 4,647,431, which issued to Takasi Sekine, et al., and an improved version of the conventional test slide described in the Sekine, et al. patent is disclosed in U.S. Pat. No. 8,287,823, which issued to James M. Sellers, et al., and U.S. Pat. No. 8,585,989, which issued to Carl Russell Rich, the disclosure of each of which is incorporated herein by reference. Automated chemical analyzers and instruments which conduct test procedures utilizing dry chemical reagent test slides are also known, such as the VETTEST® analyzer and the CATALYST DX® analyzer available from IDEXX Laboratories, Inc. of Westbrook, Me.
A very capable “dry chemistry” analyzer is described in U.S. Pat. No. 5,089,229, which issued to Thomas Heidt, et al., the disclosure of which is incorporated herein by reference. The chemical analyzer described in the aforementioned '229 Heidt, et al. patent includes a rotatable turntable which is adapted to hold a plurality of reagent test slides, a sample metering device, an incubator or temperature controller, a reflectometer, a slide inserter mechanism, a slide ejector mechanism and associated electronics, computer or microprocessor, and software. The rotatable turntable preferably holds up to twelve slides about its circumference. The dry analytical test slides come individually pre-packaged, and are inserted by the operator onto the rotatable turntable one at a time by using the inserter mechanism. The turntable positions the reagent test slides under the metering device, which device deposits a predetermined amount of sample onto each slide. The turntable also carries the slides above a reflectometer. After testing has been completed, the ejector mechanism automatically removes the reagent test slides from the turntable.
An improved automated analyzer which utilizes reagent test slides is described in U.S. Patent Application Publication No. 2010/0254854, filed on Nov. 5, 2009, and naming Carl Russell Rich, et al. as the inventors, the disclosure of which is incorporated herein by reference. The Rich, et al. published application discloses a chemical analyzer which includes a slide transport mechanism, a slide inserter mechanism which inserts a plurality of chemical reagent test slides onto the slide transport mechanism, a reflectometer/fluorometer which is positioned in proximity to the slide transport mechanism and the chemical reagent test slides situated thereon, a sample metering device that aspirates a sample fluid from a vial or centrifuge rotor and deposits a predetermined volume of the sample fluid onto the chemical reagent test slides, an incubator for maintaining the reagent test slides situated on the slide transport mechanism at a predetermined temperature, and a slide ejector mechanism which removes the reagent test slides from the slide transport mechanism.